The present invention relates to a method and apparatus for joining a sealing or closure element to a cylindrical container sleeve, said sealing or closure element having a circular collar and being arranged to be introduced into one, open end of said sleeve into abutment with the inner wall thereof, and in which at least the collar comprises a heat-meltable plastics material.
The primary object of the invention is to provide a positive and tight seal between the sealing or closure element and the sleeve, irrespective of the type of meltable plastics material incorporated in the collar, and optionally also in the sleeve.
In the storage of certain liquids and oils, the closure elements need to be made of a high-density plastics and the container sleeves provided with an inner foil also comprising a high density plastics material. These plastics are extremely difficult to bond together quickly by heat-welding processes, and the invention is particularly, although not exclusively, concerned with work in connection with these plastics. The invention, however, can also be applied to advantage when a collar or a flange made of any meltable plastics material is to be joined to a ring-shaped inner end portion of a cylindrical container sleeve comprising uncoated or coated board, cardboard, paper, sheet-metal or the like.